21.  Nowadays some people say that if Marx were alive at the end of the 20th century, he would replace religion with television.

22.  If he was alive at the end of the 20th century, he would replace religion with television.

23.  Otherwise he might replace religion with television and say that "television is the opium of the masses".

24.  If Marx was alive at the end of the 20th century, he would replace religion with television.

25.  If he was alive at the end of the 20th century, he would replace religion with the television.

26.  The Color-TV has replaced the black-and-white TV.

27.  As a result, most old soldiers should be replaced by the new ones.

28.  As time goes on, it will be replaced by more effective system.

29.  If not happily Married, they would replace their Marriage with their children as the hope of the latter half of their life.

30.  The farmhouse was replaced by factories with chimneys emitting black smoke.